Previous Article | Next Article ![]()
Molecular and Cellular Biology, December 2007, p. 8670-8682, Vol. 27, No. 24
0270-7306/07/$08.00+0 doi:10.1128/MCB.00635-07
Copyright © 2007, American Society for Microbiology. All Rights Reserved.
,
Center for Cancer and Stem Cell Biology, Alkek Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, Texas 77030
Received 11 April 2007/ Returned for modification 26 June 2007/ Accepted 21 September 2007
The nucleolus has begun to emerge as a subnuclear organelle capable of modulating the activities of nuclear proteins in a dynamic and cell type-dependent manner. It remains unclear whether one can extrapolate a rule that predicts the nucleolar localization of multiple proteins based on protein sequence. Here, we address this issue by determining the shared and unique mechanisms that regulate the static and dynamic distributions of a family of nucleolar GTP-binding proteins, consisting of nucleostemin (NS), guanine nucleotide binding protein-like 3 (GNL3L), and Ngp1. The nucleolar residence of GNL3L is short and primarily controlled by its basic-coiled-coil domain, whereas the nucleolar residence of NS and Ngp1 is long and requires the basic and the GTP-binding domains, the latter of which functions as a retention signal. All three proteins contain a nucleoplasmic localization signal (NpLS) that prevents their nucleolar accumulation. Unlike that of the basic domain, the activity of NpLS is dynamically controlled by the GTP-binding domain. The nucleolar retention and the NpLS-regulating functions of the G domain involve specific residues that cannot be predicted by overall protein homology. This work reveals common and protein-specific mechanisms underlying the nucleolar movement of NS family proteins.
Published ahead of print on 8 October 2007.
Supplemental material for this article may be found at http://mcb.asm.org/.
This article has been cited by other articles:
Copyright © 2009 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»